A brake device provided with a vehicle is mainly used when a moving vehicle is decelerated and disposed to stop the vehicle by applying a braking force to wheels by the brake operation executed by depressing a brake pedal by the driver of the vehicle. Although the brake device is disposed to stop the vehicle by the brake operation of the driver as described above, in some of conventional brake devices, the braking force, which is generated by the depression force when a driver depresses a brake pedal at the time of a quick stop, is insufficient to a braking force necessary to the quick stop, the braking force is secured by increasing the brake fluid pressure applied to wheel cylinders provided with the brake devices by pumps.
Further, some of the conventional brake devices execute an anti-lock control which is a control for suppressing wheels from being locked by controlling the braking force applied to the wheels when the wheels are locked in at the time of a quick stop and execute a vehicle stop keeping control, which is a control for keeping a vehicle stop state by applying a braking force to the wheels even when a foot is removed from a brake pedal when the vehicle stops for the purpose of reducing a burden on the driver in a hill start assist, waiting at a red light, a traffic jam, and the like. In these controls, the braking force is controlled by controlling the brake fluid pressure by the pumps likewise the case in which the brake pressure is increased in the quick stop.
For example, a brake device for vehicle described in Patent Document 1 is disposed with pumps capable of circulating a brake fluid of a piping system, a proportional control valve capable of keeping a brake fluid pressure of the piping system on the wheel cylinders side, and a pressure reduction control valve capable of reducing the brake fluid pressure applied to the wheel cylinders. With the configuration, when the brake fluid pressure applied to the wheel cylinders at the time of a quick stop is increased, the brake fluid pressure applied to the wheel cylinders can be increased by placing the brake fluid to be flown to the wheel cylinders side in the state that the brake fluid can be increased by operating the pumps and by keeping the brake fluid pressure of the piping system on wheel cylinders side by the proportional control valve. Further, when an anti-lock control is executed, wheels can be suppressed from being locked by reducing a braking force when the wheels are locked by returning a part of the brake fluid of the piping system on the wheel cylinders side to the pumps side by opening pressure reduction control valves disposed to a piping system toward the wheel cylinders and positioned upstream of the pumps while circulating the brake fluid by operating the pumps.
As described above, a braking force different from the brake operation of a driver can be generated in the brake device by disposing the pumps capable of circulating the brake fluid to the brake device and the proportional control valve capable of keeping the brake fluid pressure of the piping system on the wheel cylinders side to the brake device and controlling them in response to the state at the time of braking.    Patent Document 1: Japanese Patent Application Laid-open No. H09-254762